Moons of Neptune
| Moons on Pluto |
| Name |
Mean diameter (km) |
Mass (×1021 kg) |
Semi-major
axis (km) |
Orbital period (days) |
Discovery date |
| Pluto |
2390 |
13.05 ± 0.07 |
2 035* |
6.387 230 |
1930 |
| Pluto I |
Charon |
1207 ± 3 |
1.52 ± 0.06 |
17 536 ± 3* |
6.387 230 |
1978 |
| Pluto II |
Nix |
46-137 |
< 0.002 |
48 708 |
24.856 ± 0.001 |
2005 |
| Pluto III |
Hydra |
61-167 |
< 0.002 |
64 749 |
38.206 ± 0.001 |
2005 |
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